Substrate processing method and apparatus

ABSTRACT

Disclosed herein is a method for processing a substrate. The method includes supplying a liquid agent such as a developer onto the surface of a substrate, bringing an upper surface of a film formed of the liquid agent into contact with a liquid agent holding member arranged so as to face the substrate, holding the liquid agent between the substrate and the liquid agent holding member, moving the substrate or the liquid agent holding member, or both, in parallel to the main surface of the substrate, while the main surface of the substrate is being treated with the liquid agent. Since the concentrations of reaction products and starting reaction materials become uniform in the liquid agent which contacts the substrate, the entire substrate can be processed uniformly.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a substrate processing methodand apparatus for use in a semiconductor device, a liquid crystaldisplay and the like. More specifically, the present invention relatesto a method and apparatus for processing a substrate by using a liquidagent.

[0002] In the semiconductor device and liquid crystal display, desiredfunctions can be imparted by applying various types of processing to asubstrate and forming a micro pattern on the substrate. To process thesubstrate as mentioned above, not only a dry process using a gas butalso a wet process using a liquid agent is widely employed. The wetprocessing is performed to develop a photosensitive resist pattern,which will be used to form a micro pattern.

[0003] To form a photosensitive resist pattern, a photosensitive resistis applied on a film which has been formed on a silicon or quartzsubstrate, thereby forming a photoresist film. An exposure mask isplaced above the photoresist film. Light is applied through the mask,whereby a desired region of the resist film is exposed to light.Subsequently, the light-exposed portion of the resist film, if theresist film is a positive type one, or the non light-exposed portion, ifthe resist film is a negative type one, is removed with an organicsolvent or an aqueous alkaline solution. As a result, a photosensitiveresist pattern is formed.

[0004] To form a chromium mask for use in light exposure, the wetprocess is applied. After the chromium film is formed on a substrate, aphotosensitive resist pattern is formed. Those parts of the chromiumfilm which are not covered with the resist pattern are isotropicallyremoved by the wet-etching using a ceric nitrate ammonium solution.

[0005] To remove unnecessary organic materials from a substrate prior toprocessing, or to remove the photosensitive resin pattern from asubstrate after completion of etching, a mixed liquid agent consistingof sulfuric acid and hydrogen peroxide is used.

[0006] If a silicon substrate is reacted with oxygen contained in theair, a native oxide film will be formed. Since the native oxide filmprevents uniform processing, it must be removed. To remove the nativeoxide film, a liquid agent such as NH₄ or diluted HF is applied.

[0007] In the case where a gold film is formed on a silicon substrate,an Au plating solution is used.

[0008] Wet processing methods include a dip treatment in which thesubstrate is dipped in a liquid agent, and a puddle treatment in whichthe substrate is treated with a liquid agent supplied to the mainsurface of the substrate. However, the dip treatment has problems inthat a large amount of the liquid agent is required and in that thesubstrate may be contaminated with a material present in the rearsurface. Because of the problems, the paddle treatment tends to bewidely employed rather than the dip treatment. To perform the puddletreatment, the substrate is fixed at the back by a vacuum chuck (Jpn.Pat. Appln. KOKAI Publication No. 7-235473).

[0009] In the wet treatment, the treatment is performed through achemical reaction between a liquid agent and the film to be treated. Asthe treatment proceeds, the concentration of reaction productsincreases, whereas that of the starting liquid agent decreases. Sincethe reaction products and the starting liquid agents do not diffuseimmediately, their concentrations varies locally. Consequently, thesurface of the film cannot always processed uniformly.

[0010] In a developing method, for example, resist is removed from adesired region of the substrate with an aqueous alkaline solution and isdissolved by a neutralization reaction with the developer (aqueousalkaline solution). This is because the resin forming a resist removalregion has an acidic group such as a carboxylic acid or a phenol groupas a side chain. The substrate is brought to a standstill in aconventional development step, so that the dissolved resin diffusesslowly. As a result, the dissolved resin is left near the resist removalregion. In addition, an OH group does not diffuse sufficiently fast. Theconcentration of the OH group is therefore locally low after the OHgroup is consumed in the neutralization reaction. This reduces local pH.The volume of the resin in the removal region, i.e., the amount of theresin to be dissolved, depends on a pattern. Hence, the dimensions ofthe photosensitive resist finally left on the substrate surface is notuniform.

[0011] Then, the aforementioned publication No. 7-235473 discloses thefollowing method using a rotation-type resist developing apparatus. Inthis apparatus, a capillary action is induced in the treatment solutionbetween the wafer and the liquid agent supply board located in proximityof the wafer. The time required for dispersing the treatment solutionover the resist film can, therefore, be reduced by the capillary actionand thereby uneven development decreases. However, in this method,development is carried out at a predetermined time interval after thedeveloper is dispersed over the entire surface of the resist film. Thus,the local change in pH of the developer inevitably occurs, as mentionedabove.

[0012] In the case where the developing process is performed whilestirring the developer, an ultrasonic oscillator is employed asdisclosed in a method of Jpn. Pat; Appln. KOKAI Publication No.57-208134. However, when the ultrasonic oscillator is used, voids areproduced or destroyed in the liquid agent by the cavitation effect dueto the oscillation. Since the substrate has larger acoustic impedancethan the liquid agent, the void tends to form, especially on thesubstrate. Due to voids, the liquid agent does not always contact thesubstrate. As a consequence, the substrate surface cannot be processeduniformly.

BRIEF SUMMARY OF THE INVENTION

[0013] The present invention relates to a substrate processing methodand apparatus for treating a substrate with a liquid agent. The objectof the present invention resides in that reaction products and startingreaction materials are present in uniform concentrations in the liquidagent in contact with a entire surface of the substrate, and that thesubstrate can be processed uniformly over its surface after it has beentreated.

[0014] A main feature of the present invention resides in that asubstrate or a liquid agent holding member, or both are moved inparallel to the main surface of the substrate during the treatment withthe liquid agent while the liquid agent remains in contact with theliquid agent holding member. The liquid agent is thereby stirred. Thereaction products and the starting reaction materials are thereforepresent in uniform concentrations in the liquid agent which contacts thesurface of the substrate. As a result, the substrate can be processed,over its surface, with uniform accuracy after it has been treated. Inaddition, since the liquid agent is stirred, it is possible to preventthe reaction products from accumulating near the substrate surface andto maintain the concentration of the starting reaction materials. Theprocessing rate therefore can be improved.

[0015] To attain the aforementioned object, the substrate processingmethod according to a first aspect of the present invention comprises:

[0016] a first step of supplying a liquid agent onto a main surface of asubstrate;

[0017] a second step of holding the liquid agent between the substrateand a liquid agent holding member by bringing an upper surface of a filmof the liquid agent in contact with the liquid agent holding memberwhich faces the substrate; and

[0018] a third step of moving at least one of the substrate and theliquid agent holding member in parallel to the main surface of thesubstrate, after the second step, in order to treat uniformly the mainsurface of the substrate with the liquid agent.

[0019] The second step may include a step of using a liquid agent supplynozzle as the liquid agent holding member.

[0020] The first step desirably includes a step of applying the liquidagent, by use of a disc nozzle with plural liquid agent outlet holes orby use of a linear nozzle which has a linear developer supply sectionwhose length is almost the same as a diameter of the wafer whilerotating the substrate or moving the linear nozzle from one end of thesubstrate to the other in parallel to the main surface of the substratewhich is at a sandstill.

[0021] It is desirable that the second step include a step of moving theliquid agent holding member so as to face the substrate and bringing theliquid agent holding member in contact with an upper surface of the filmof the liquid agent.

[0022] It is desirable that the third step include a step of performingreciprocating movement or rotational movement.

[0023] It is desirable that the rotational movement include rotating thesubstrate while the liquid agent holding member is immobilized.

[0024] It is desirable that the velocity of the rotational movement is10 to 50 rpm.

[0025] It is desirable that the first step include a step of forming asingle liquid-agent film on a surface of the liquid agent supply nozzlefacing the substrate, supplying the liquid agent to the main surface ofthe substrate in the form of film, and using the liquid agent supplynozzle as the liquid agent holding member.

[0026] The first step may include a step of supplying the liquid agentto an entire surface of the substrate substantially at the same time.

[0027] The first step may include a step of supplying the liquid agentby using the liquid agent supply nozzle having the surface made in aconvex form.

[0028] The first step may include a step of supplying the liquid agentonto the main surface of the substrate while a substrate surface facingthe liquid agent supply nozzle remains in a convex form.

[0029] The first step may include a step of supplying the liquid agentwhile reducing pressure in a space provided between the substrate andthe liquid agent supply nozzle.

[0030] The liquid agent may be one selected from the group consisting ofa developer, an etching solution, a washing solution, a remover agent, afilm formation solution and a plating liquid.

[0031] It is desirable that the substrate processing method furthercomprise a step of simultaneously rinsing the liquid agent holdingmember and the main surface of the substrate by replacing the liquidagent with a rinse solution after the third step.

[0032] The reciprocating movement or rotational movement in parallel tothe main surface of the substrate may be performed by any one of thesteps: (a) the liquid agent holding member is moved while the substrateis fixed; (b) the substrate and the liquid agent holding member arerelatively moved to each other in the same direction; (c) the substrateand the liquid agent holding member are relatively moved in a reversedirection to each other; and (d) the substrate or the liquid agentholding member is moved back and forth, while the other is rotated.

[0033] The substrate processing apparatus according to a second aspectof the present invention comprises:

[0034] a table on which a substrate is to be mounted;

[0035] a liquid agent supply nozzle for supplying a liquid agent onto amain surface of the substrate;

[0036] a liquid agent holding member facing the substrate and movable upand down in order to be in contact with an upper surface of thefilm-form liquid agent; and

[0037] a mechanism for moving at least one element of the substrate andthe liquid agent holding member in parallel to the main surface of thesubstrate while the liquid agent holding member is in contact with theupper surface of the film-form liquid agent.

[0038] The liquid agent supply nozzle may serve as the liquid agentholding member.

[0039] The mechanism desirably includes a reciprocating drive mechanismor a rotational drive mechanism.

[0040] The liquid agent supply nozzle desirably has a plurality ofliquid agent outlet holes in a surface facing the substrate, any two ofthe liquid agent outlet holes adjacent to each other in a movingdirection of the substrate passing through different regions of thesubstrate when the nozzle moves relative to the substrate.

[0041] The liquid agent supply nozzle has a plurality of liquid agentoutlet holes in a surface facing the substrate, the liquid agent outletholes being uniformly distributed in a plane facing the substrate.

[0042] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0043] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0044]FIG. 1 is an example of an entire structure of a system of acoating/developing apparatus of the present invention includingperipheral units;

[0045]FIG. 2 is a schematic cross-sectional view of a development unitaccording to Embodiment 1 of the present invention;

[0046]FIG. 3 is a schematic plan view of a development unit according toEmbodiment 1 of the present invention;

[0047]FIG. 4A is a perspective plan view of a disk nozzle of thedevelopment unit according to Embodiment 1;

[0048]FIG. 4B is a cross sectional view taken along the line 4B-4B ofFIG. 4A;

[0049]FIG. 5 is a characteristic graph showing the dependency of themeasured dimensions of patterns on a wafer upon the wafer rotationvelocity, in Embodiment 1;

[0050]FIG. 6 is a schematic sectional view of the disk nozzle and thewafer for showing the relationship between the wafer rotation velocity(VW) and the rotation velocity (VD) of the developer;

[0051]FIG. 7 is a schematic sectional view of the development unitaccording to Embodiment 2 of the present invention;

[0052]FIG. 8 is a schematic plan view of the development unit accordingto Embodiment 2;

[0053]FIGS. 9A and 9B are a cross sectional view and a bottom view,respectively, of the linear nozzle according to Embodiment 2 forexplaining the structure thereof;

[0054]FIGS. 10A and 10B are perspective views sequentially showing thedeveloper coating method according to Embodiment 2;

[0055]FIGS. 11A and 11B are a cross sectional view and a front view,respectively, of another example of the nozzle according to Embodiment2, whose developer supply section is a slit;

[0056] FIGS. 11C-11G are cross sectional views showing modified examplesof FIG. 11A, which supply the developer not only in the downwarddirection but also in the opposite direction to the nozzle movingdirection;

[0057]FIG. 11H is a perspective view of a nozzle having a plurality ofsmall passages between a developer storing portion and a slit, as astill another example of Embodiment 2;

[0058]FIG. 12 is a cross sectional view of a linear nozzle and a waferaccording to a modified example of Embodiment 2, for explaining a methodhow to stir the developer by the linear nozzle;

[0059]FIG. 13A is a schematic plan view of the liquid agent holdingmember of a development unit according to Embodiment 3 of the presentinvention;

[0060]FIG. 13B is a cross sectional view taken along the line 11B-11B ofthe FIG. 11A;

[0061]FIG. 14 is a plan view of a conventional disk nozzle, for showingthe position of an outlet hole;

[0062]FIG. 15 is a partial plan view of a substrate for showing adeveloping region of the substrate in the case where the disk nozzle ofFIG. 14 is used;

[0063]FIG. 16 is a plan view of a disk nozzle according to Embodiment 4of the present invention, for showing the position of the disk nozzle;

[0064]FIG. 17 is a partial plan view of the substrate for showing adeveloping region of the substrate in the case where the disk nozzle ofFIG. 16 is used;

[0065]FIG. 18 is a plan view of a modified example of the disk nozzleaccording to Embodiment 4;

[0066]FIG. 19 is a plan view of another modified example of the disknozzle according to Embodiment 4;

[0067]FIG. 20 is a partial cross-sectional view of a disk nozzleaccording to Embodiment 5, for explaining a development method in whichdevelopment is initiated by bringing a developer film, which is formedby the use of surface tension of the developer, to be contact with thewafer;

[0068]FIG. 21 is a cross-sectional view of the disk nozzle includingperipheral structural elements, explaining that development is initiatedin Embodiment 5 by dropping, onto a wafer surface, the developer filmformed by virtue of the surface tension;

[0069] FIGS. 22A-22C are sequential cross sectional views of the disknozzle according to Embodiment 6, explaining how to prevent foamgeneration when the developer film is formed by a disk nozzle having aslightly protruding center; and

[0070]FIG. 23 is a cross-sectional view of the disk nozzle of thedevelopment unit according to Embodiment 7, explaining how to mount thedeveloper by evacuating a space between the disk nozzle and the wafer bymeans of a liquid and air pump.

DETAILED DESCRIPTION OF THE INVENTION

[0071] Now, embodiments of the present invention will be explained withreference to the accompanying drawings.

Embodiment 1

[0072] In the developing step of a photosensitive resist pattern of thisembodiment, a developer supply nozzle is used as a liquid agent holdingmember, and a developer is stirred by rotational motion in a directionparallel to a wafer surface. FIG. 1 shows an example of a system used inEmbodiment 1. The system comprises a coating/developing apparatus andperipheral apparatuses (exposure apparatus and the like).

[0073] The coating/developing apparatus is composed of a cassettestation 101, a processing station 102, and an interface section 103. Thecoating/developing apparatus 104 is connected to an exposure apparatus104 by the interface section 103.

[0074] The cassette station 101 is designed to load and unload a wafercassette (not shown) into and from the system. The wafer cassette storesa plurality of substrates, more specifically, semiconductor wafers (notshown, hereinafter referred to as “wafers”). The cassette holds, forexample, 25 wafers at a time. The cassette station 101 is designed alsoto load wafers from the wafer cassette into the processing station 102,and vise versa.

[0075] The process station 102 has various single wafer processingunits, each designed to process one wafer at a time in the developingand coating steps. The processing units are arranged one above another,in stages. Each processing unit processes wafers, one by one. Theprocess station 102 is composed of a coating unit 105, a developmentunit 106, and an oven-type processing unit 107. The coating unit 105 andthe development unit 106 are spinner type units, in which apredetermined treatment is applied to the wafer mounted on a spin chuckplaced in a cup. The unit 105 coats a wafer with a resist film and ananti-reflection film. The unit 106 develops the resist film.

[0076] The oven-type processing unit 107 is designed to perform apredetermined treatment on the wafer mounted on a table. The unit 107includes a cooling unit 108, an adhesion unit 109, an alignment unit110, an extension unit 111, a pre-baking unit 112, a post-exposurebaking unit 113, and a baking unit 114. These units 108 to 114 arestacked, one upon another. The cooling unit 108 cools wafers. Theadhesion unit 109 performs hydrophobic treatment to enhance resistadhesion. The alignment unit 110 is designed to align wafers. Thepre-baking unit 112 is provided for heating wafers prior to lightexposure. The post-exposure baking unit 113 is used to heat wafers afterlight exposure treatment. In the interface section 103, wafers aretransferred from the processing station 102 to the exposure apparatus104, and vice versa.

[0077] The wafer is processed as follows. At first, a predeterminednumber of wafers are loaded into the wafer cassette. The wafer cassetteholding the wafers is set at the cassette station 101. A wafer istransported from the cassette station 101 to the cooling unit 108 whichis provided in the oven-type processing unit 107. The wafer is cooled inthe cooling unit 108 for 40 seconds and then transported to theanti-reflection film coating unit 105. In the unit 105, the wafer iscoated with an anti-reflection film having a thickness of 60 nm. Thewafer is further transported to the baking unit 114 heated to 175° C.within the oven-type processing unit 107. In the baking unit 114, thewafer is heated for 60 seconds.

[0078] Thereafter, the wafer is transported to the cooling unit 108 andcooled at 23° C. for 60 seconds. The wafer thus cooled is transported tothe resist coating unit 105. In the unit 105, resist is applied onto thewafer, and a positive type photosensitive resist is applied onto thewafer, forming a film having a thickness of 0.3 μm. Thereafter, thewafer is transported to the pre-baking unit 112 heated to 100° C. whichis provided in the oven-type process unit 107. In the unit 112, thewafer is pre-baked 90 seconds.

[0079] The wafer thus pre-baked is transported to the cooling unit 108and is cooled at 23° C. for 60 seconds. The wafer is then transferred tothe interface section 103 and then loaded into the exposure apparatus104. The wafer is exposed to light under normal conditions: NA=0.55,σ=0.55. Thereafter, the wafer is introduced into the coating/developingapparatus through the interface section 103 and then heated at 100° C.for 90 seconds in the post exposure baking unit 113.

[0080] The development unit according to this embodiment will bedescribed.

[0081]FIGS. 2 and 3 are, respectively, cross-sectional view and planview of the developing unit incorporated in the coating/developingapparatus of the present invention. A circular cup CP is provided at acenter portion of the development unit. The cup CP contains a spin chuck201. A motor 202 is provided to rotate the spin chuck 201, while thewafer is held by vacuum adsorption. The driving motor 202 is fitted inan opening made in the bottom plate 203 of the developing unit. Themotor 202 is connected to a driving means 205 (including for example, anair cylinder) and a guiding means 206 by a cap-shaped aluminum flangemember 204. Hence, the motor 202 can be moved up and down. Acylinder-form cooling jacket 207 made of, e.g., SUS, is fixed to a sideof the driving motor 202. The flange member 204 is fixed, covering thehalf of the cooling jacket 207.

[0082] To apply the developer to the wafer, the lower edge of the flangemember 204 is brought into airtight contact with the outer periphery ofthe opening made in the unit bottom plate 203. The developing unit isthereby sealed airtight. To transfer the wafer W between the spin chuck201 and the wafer transfer mechanism (not shown), the flange member 204is lifted apart from the unit bottom plate 203 by the driving means 205.In this manner, the driving motor 202 and the spin chuck 201 are lifted,together with the flange member 204.

[0083] A developer supply pipe 209 connects a developer supply nozzle208 to a developer source (not shown). Developer can therefore besupplied from the nozzle 208 to the surface of the wafer surface. Thenozzle 208 is removably attached to a distal end of a nozzle scan arm210 by a nozzle holder 211. The scan arm 210 is secured to an upper endof a vertical support member 213. The support member 213 can move alonga guide rail 212, which is provided on the unit bottom plate 203 in adirection Y direction. Thus, the member 213 can move in the Y directionwhen driven by a Y-direction drive mechanism (not shown).

[0084] The developer supply nozzle 208 has substantially the same shapeas the wafer W, as is shown in FIG. 3. More specifically, the developersupply nozzle 208 is shaped like a disk, slightly larger than the waferW. While the wafer W is being rotated, the developer is supplied fromthe disk-shaped developer supply nozzle (disk nozzle) 208, over theentire surface of the wafer W. The nozzle 208 is attached to the distalend of the nozzle scan arm 210, as described above. The nozzle 208 movesback and forth on the guide rail 212 in the Y direction, between aposition, where it faces the wafer W, and a stand-by position 214. Thestand-by position 214 is at a side of the wafer W, as is illustrated inFIG. 3. Instead, the stand-by position 214 may be provided above thewafer W.

[0085] A rinse nozzle 215 is provided for discharging a washingsolution. The rinse nozzle 215 is secured to a distal end of the nozzlescan arm 216, which can move on the guide rail 212 in the Y direction.After completion of the developing process with the developer, the rinsenozzle 215 is moved over the wafer W to apply the washing solution tothe wafer W.

[0086] How the developing process is performed in the developing unit106 will be explained.

[0087] After the post exposure baking process described above, the waferW is transferred to the developing unit 106 (FIG. 1). In the unit 106,the wafer is fixed onto the spin chuck 201. The developer supply nozzle208, which has substantially the same shape as the wafer W, is locatedabove the wafer W and faces the wafer W. The nozzle 208 has a pluralityof holes of 0.5 mm in diameter, in the surface that opposes the wafer W.The holes are arranged at intervals of 4 mm. The nozzle 208 is spaced bya distance of 2 mm from the upper surface of the wafer W.

[0088] First, the disk-shaped developer supply nozzle 208 applies thedeveloper to the entire surface of the wafer W, while the wafer W isbeing rotated at 60 rpm. A developer film is thereby formed on the waferW to a thickness of 2 mm.

[0089] The state at this time point is shown in FIGS. 4A and 4B. FIG. 4Ais a partial perspective plan view of the development unit. FIG. 4B is across-sectional view of the development unit taken along the line 4B-4Bof FIG. 4A. The space between the disk nozzle 208 and the wafer W isfilled with the developer in the form of the developer film 244, andthus the lower surface of the disk nozzle 208 comes into contact withthe upper surface of the developer film 244.

[0090] Next, development is performed for 60 seconds, from the start ofthe application of developer to the start of application of rinsesolution supply. During the development, the wafer is rotated at 30 rpmand the disk nozzle 208 remains at a standstill. Thereafter, the disknozzle 208 is lifted to the stand-by position 214 as shown in FIG. 3.

[0091] Then, the rinse nozzle 215 is moved to the center of the wafer W.The wafer W is rotated at 2000 rpm. The developer is thereby removedfrom the wafer. At the same time, the rinse solution is applied, and thedevelopment step is terminated. Thereafter, the wafer is rotated at 500rpm to wash the wafer W. Finally, the supply of the rinse solution isterminated. The wafer W is rotated at 2000 rpm again, removing the rinsesolution from the wafer W. Thus, the wafer W is dried.

[0092] As a result, a 0.225 μm L&S (line and space) pattern is formed.The line width (critical dimension) of the L&S pattern thus formed ismeasured all over the wafer and the-line width (dimension) variation(3σ) is calculated. FIG. 5 shows the dependence of the variation 3σ onthe rotation velocity at which the wafer W is rotated while thedeveloper film remains in contact with the lower-surface of the nozzleduring development. In FIG. 5, the Y axis indicates the dimensionvariation 3σ (nm), and the X axis indicates the rotational velocity(rpm). As seen from FIG. 5, the dimension variation 3σ has the minimumvalue of 8 nm when the wafer is rotated at a rotational velocity rangingfrom 30 rpm to 40 rpm during the development. If the wafer W is notmoved at all, the variation 3σ is 20 nm. In the case of the conventionalmethod, the space between the nozzle and the wafer is set sufficientlywide for the developer liquid film applied onto the wafer not to bebrought into contact with the nozzle and the wafer is stopped duringdevelopment. In this case, the variation 3σ is 23 nm, which is shown inFIG. 5 as “disk nozzle noncontact development”. As FIG. 5 shows, itturns out that the developer can be stirred and the uniformity of thepattern dimensions can be improved, by rotating the wafer at anappropriate velocity (10-50 rpm, preferably 30-40 rpm) during thedevelopment, while the developer film remains in contact with the lowersurface of the nozzle.

[0093] The effect of this method on the uniformity improvement in resistpattern dimensions is not limited to the L&S pattern whose line andspace width is 0.225 μm. It can also be achieved for any other patterns.This advantage is attained, regardless of types and sizes of patternsand can be seen in all patterns.

[0094] Results that may be obtained by using an ultrasonic oscillatorwill be described. A developer film is formed on the wafer by using thedisk nozzle. Then, the ultrasonic oscillator applies ultrasonic waves tothe wafer for 50 seconds, while a disk which has a bottom surface of thesame shape as the wafer and which incorporates the ultrasonic oscillatorremains in contact with the upper surface of the developer liquid film.The disk is withdrawn, and the wafer is rinsed and dried in the samemanner as mentioned above. In this case, the variation 3σ is 30 nm. Thisvalue is greater than in the case where the wafer is rotated at a lowvelocity while the lower surface of the nozzle remains in contact withthe developer liquid film. The value is greater also than in the casewhere the developer is supplied by the nozzle that does not contact thedeveloper film while the wafer is not rotated during the development.Obviously, the uniformity of the wafer surface obtained after thedevelopment cannot be improved even if the ultrasonic oscillator isused. This is perhaps because the liquid agent is not always uniformlyin contact with the surface of the substrate since voids are generatedor destroyed in the liquid agent contacting the substrate, by thecavitation effect resulting from the vibration.

[0095] During the aforementioned development stirring, the wafer isrotated at a low speed and the disk nozzle in contact with the uppersurface of the developer liquid film remains at a standstill. Thestirring may be performed as will be explained with reference to FIG. 6,which is a partial sectional view of the development unit.

[0096] If the upper surface of the developer does not contact the disknozzle, the developer follows the rotational motion of the wafer. As aresult, the developer is not stirred. In addition to that the developerflows outwardly due to centrifugal force, and the developer liquid filmhas no uniform thickness, therefore the uniformity in the patterndimensions over the wafer decreases. If the upper surface of thedeveloper liquid film 244 contacts the lower surface of the disk nozzle208 as shown in FIG. 6, friction is generated between the developerliquid film 244 and the lower surface of the disk nozzle 208. Thefriction between the developer liquid film 244 and the lower surface ofthe disk nozzle 208 prevents the developer liquid film 244 from movingtogether with the wafer W. Consequently, the rotational velocity of thedeveloper liquid film 244 is lower than that of the wafer W. The liquidfilm 244 therefore moves relative to the wafer W. This prevents thelocal accumulation of the reaction products and local consumption of thestarting liquid agent in the developer liquid film 244 that contacts thewafer W, which can happen depending upon the photosensitive pattern.

[0097] Furthermore, the rotational velocity VD of the developer liquidfilm 244 near the wafer W is higher than the rotational velocity VD nearthe disk nozzle 208, because the wafer W has the rotational velocity VWand the nozzle 208 remains at a standstill. Consequently, the movingrate of the developer at the upper portion of the developer film differsfrom that at the lower portion of the developer film, as is illustratedin FIG. 6. Thus, it is presumed that stirring effect within thedeveloper film has also developed.

[0098] In the present invention, the liquid agent is stirred by movingthe upper and lower surfaces of the liquid agent film at differentspeeds. It is therefore possible to move the liquid agent over a largearea. If an ultrasonic oscillator is used, the liquid agent is slightlystirred, and the movement of the liquid agent is limited to a smallarea. With the method of the present invention it is possible to stirthe liquid agent in a large area. The method can therefore effectivelyrender the concentrations of the starting liquid agent and reactionproducts uniform. The spilling of the developer 244 due to thecentrifugal force and non-uniformity in the thickness of the liquid filmcan be prevented by the friction between the disk nozzle 208 and thedeveloper film 244, by contact of the disk nozzle with the liquid filmwith rotating the wafer W at an appropriate velocity. Hence, a developedwafer having uniform dimensions can be obtained.

[0099] In the aforementioned explanation, the wafer is rotated in aplane parallel to the wafer surface. If the wafer is moved relative tothe liquid agent holding member (developer supply nozzle or disknozzle), the same advantages as mentioned above can be obtained.Therefore, the wafer may be maintained at a standstill, whereas thedeveloper holding member is moved. Alternatively, both the holdingmember and the wafer may be moved in the same direction or in theopposite directions.

[0100] The wafer is rinsed by using a straight-tube rinse nozzle in theaforementioned embodiment. Instead, a disk nozzle may be used to rinsethe wafer. Especially, in the case that the liquid agent supply nozzleacts also as the liquid agent holding member, it is effective. Thenozzle surface can also be washed during the step of rinsing the waferif the rinse solution is supplied from the same nozzle to the wafer, andthe rinse solution contacts the nozzle for a certain time. The step toseparate the nozzle from the liquid agent is needed to remove the rinsesolution from the space between the nozzle and the wafer.

Embodiment 2

[0101] Embodiment 2 of the invention will be explained with reference toFIGS. 7 and 8.

[0102]FIGS. 7 and 8 are sectional view and plan view of an entirestructure of a development unit, respectively. The developing unit has alinear nozzle 271, which has a linear developer supply section whoselength is almost same as a diameter of the wafer. A developer holdingmember 272 is attached to the unit in addition to the developer supplynozzle 271. The member 272 faces the wafer W, and can be used tosandwich the developer between the member and the wafer. The developerholding member (stirring member) 272 is attached to the distal end of aholding member scan arm 274. The arm 274 is a drive mechanism that canmove on a guide rail 273 in the Y direction. The developer holdingmember 272 moves between a stand-by position and a position where itfaces the wafer W.

[0103] The developer supply nozzle 271 is attached to the nozzle scanarm which is secured to a supporting shaft 275, which is fixed at aposition different from the guide rail 273. The developer supply nozzle271 moves toward or away from a position near the wafer W when thenozzle scan arm is moved upwards or downwards. Alternatively, thesupporting shaft supporting the nozzle scan arm may be mounted onanother guide rail which is provided at some distance from the guiderail 273 and may move on another guide rail.

[0104] The linear nozzle has at least a developer storing portion and alinear developer supply section. The developer storing portion storesthe developer supplied by developer supply tubes. The developer supplysection has almost the same length as a diameter of the wafer. FIGS. 9Aand 9B show one example of the linear nozzle, which are used in thisembodiment. There is a developer-storing portion like a box containerinside the nozzle. The center portion of the bottom protrudes as shownin FIG. 9A. There is the developer supply section at the protrudedportion. The developer supply section is made of small holes (developeroutlet holes) arranged in a line. The diameter of the holes is 0.4 mmand the interval between the adjacent two holes is 2 mm. The developersupply section has almost the same length as the diameter of the wafer.The length of the developer supply section is not needed to be longerthan the diameter of the wafer, because the developer spreads afterdischarge from the nozzle holes. The width of the nozzle isapproximately 35 mm. After the developer is stored in the developerstoring portion, the developer is supplied on the wafer as it seepsthrough the small holes (developer outlet holes) on the bottom of thenozzle.

[0105] After post-exposure baking has been performed in the same way asin Embodiment 1, the wafer W is moved into the development unit and heldimmovable by the spin chuck.

[0106] The nozzle 271 first moves downwards as the arm 276 moves down.The protruding portion of the nozzle bottom is spaced apart from thewafer by a distance of 2 mm. While the wafer is being rotated at 1000rpm for 2 seconds, the developer is applied from the nozzle and spreadover the surface of the wafer W. Then, the developer is supplied to thewafer while the wafer W is being rotated at 30 rpm for 2 seconds,forming a developer liquid film on the wafer W as shown in FIG. 10A. Thelinear nozzle 271 is lifted as the arm 276 moves upwards.

[0107] The developer holding member 272 is moved to face the wafer asthe scan arm 274 moves along the guide rail 273. The member 272 is thenmoved down until it contact the developer. The development is performedfor 45 seconds, while the wafer is being rotated at 30 rpm as shown inFIG. 10B. The development time of 45 seconds has been determined so thata period of 60 seconds passes from the start of applying the developerto the start of applying the rinse solution. This period includes thetime (5 seconds) for moving the nozzle and the developer holding memberand the time (6 seconds) for moving the developer holding member and therinse nozzle. The development time may be changed in accordance with thedevelopment conditions.

[0108] The developer is held by the developer holding member 272 betweenthe wafer and the developer holding member 7, instead of the developmentnozzle 208 shown in FIG. 4B. The same advantages can be obtained as inEmbodiment 1.

[0109] Thereafter, a rinse solution is supplied with the wafer rotatedat 2000 rpm, whereby the developer is removed from the wafer W, and thedevelopment is thus terminated. The wafer W is washed with a rinsesolution while the wafer is being rotated at 500 rpm. Finally, thesupply of the rinse solution is stopped, and the wafer W is rotated at2000 rpm, whereby the rinse solution is removed from the wafer W, andthe wafer W is dried.

[0110] In this case, the line width (dimension) variation (3σ) over awafer was 8 nm for an L&S pattern whose line width and space width is0.225 μm, as in the first embodiment. Obviously, if the developer liquidfilm contacts the developer holding member and if the wafer is rotatedat an appropriate rotation number, the developer can be stirred toimprove the pattern dimension uniformity.

[0111] The developer holding member has the same shape as the wafer W.Nonetheless, the developer holding member may have a different shape.

[0112] Further, the linear developer nozzle 271 having a number of smallholes may be replaced by other types of linear nozzle. The developersupply section may be made of a narrow slit or made of plural openingslike ellipses or slits. For example, FIGS. 11A and 11B show a developersupply section having a narrow slit. Otherwise, a nozzle supplying thedeveloper in the opposite and downward direction of the nozzle movement,in stead of supplying the developer downwards just below the nozzle, maybe used, as shown in FIGS. 11C-11G. In addition to those, a nozzle thathas small passages between the developer storing portion and thedeveloper supply section may be used, as shown in FIG. 11H. The role ofthe small passages is to make the pressure of the developer uniform.Alternatively, a disk nozzle or parallel nozzles may be used to applythe developer to the wafer W. Furthermore, any other types of developersupply nozzles may be employed.

[0113] As indicated above, the developer is applied to the rotatingwafer W from the nozzle 271 that has been immobilized. Instead, thedeveloper may be applied onto the immobilized wafer from a linear nozzlewhose developer supply section has the same length as the waferdiameter, while the nozzle being moved over the wafer, in one directionparallel to the wafer W from one side to the other.

[0114] The stand-by position for the developer holding member may be setabove the wafer W, not at one side of the wafer as described above.

[0115] In Embodiment 1, the developer is supplied from the disk nozzleand then stirred by the disc nozzle. In Embodiment 2, the developer issupplied from the linear nozzle and stirred by the developer holdingmember. The present invention is not limited to these embodiments. Thenozzle which has such a shape as to hold the developer can be used notonly to apply the developer but also to stir the developer. A modifiedembodiment, which has a linear nozzle, will be explained below.

[0116] The nozzle 271 used in the modified embodiment is similar to thenozzle incorporated in Embodiment 2, but has its lower edge located at adistance of 0.5 mm from the upper surface of the wafer W. The lower endof the nozzle 271 can therefore contact the developer applied to thewafer W. After the developer is supplied onto the wafer in the samemanner as in Embodiment 1, the wafer is continuously rotated at 30 rpm.The wafer is developed for 50 seconds while being rotated as mentionedabove. The development time of 50 seconds has been determined so that aperiod of 60 second may pass from the start of application of thedeveloper to the start of application of the rinse solution. The60-second period includes the time of 4 seconds for applying thedeveloper and the time of 6 seconds for moving the nozzle and the rinsenozzle. Thus, the developer is held between the nozzle bottom and thewafer as shown in FIG. 12. The same advantages can be obtained as inEmbodiment 1.

Embodiment 3

[0117] Embodiment 3 will be explained with reference to FIGS. 13A and13B.

[0118] As shown in FIGS. 13A and 13B, the developer applied to the waferW can be effectively stirred by moving the developer holding member 291in parallel to the wafer surface. For example, a guide rail is providedin the same manner as shown in FIGS. 7 and 8. The developer holdingmember 291 is secured to a drive mechanism, which can freely move on theguide rail, enabling the holding member to move between a stand-byposition and a position where the holding member faces the wafer. Theholding member must be moved repeatedly at high speed during thedevelopment process. Therefore, a motor drives the holding member tomove at a sufficiently high speed.

[0119] In FIGS. 13A and 13B, a developer holding board is provided whichis larger than the wafer is used to stir the developer. The holdingboard may be replaced by a holding board smaller than the wafer.

[0120] Embodiments 1 to 3 show the case that at least one element of thewafer and the developer holding member is rotated or reciprocated inparallel to the main surface of the substrate. Of course, one of thewafer and the developer holding member may be rotated and the other maybe reciprocated in parallel to the main surface of the substrate.

Embodiment 4

[0121] Embodiment 4 of the present invention will be described withreference to FIGS. 14 to 19.

[0122]FIG. 14 is a plan view of a conventional disk nozzle (developersupply nozzle) 1000 which has outlet holes. FIG. 15 a partial plan viewof the development region 1105 of a wafer, over which an outlet holeshown in FIG. 14 passes. FIG. 16 is a plan view of a disk nozzle 1200according to Embodiment 4, which has outlet holes. The disk nozzle 1200corresponds to the portion 208 in Embodiment 1. FIG. 17 is a partialplan view of the development region 1205 of the wafer, over which theoutlet holes shown in FIG. 16 passes. FIGS. 18 and 19 show twomodifications of the disk nozzle 1200, which differ in the arrangementof the outlet holes. In FIGS. 14, 16, 18, and 19, the broken circlesfacilitate the arrangement of the outlet holes.

[0123] As shown in FIG. 14, the conventional disk nozzle 1000 has aplurality of outlet holes 1002, 1003, 1004 . . . . The outlet holes arearranged in concentric circles. If the developer is applied to a waferby the conventional disk nozzle 1000, however, the wafer will fail tohave uniform pattern dimensions over the wafer. This is because thedeveloper present in each outlet hole and the developer existing at theupstream of the outlet hole will diffuse into each other, especially atthat portion of the wafer which is located right below the outlet hole.The developer applied at this portion is fresher than the developerapplied to the other portions of the wafer. As a consequence, the waferis developed faster at the portions right below the outlet holes than atthe other portions.

[0124] Even if the wafer is rotated around the nozzle 1001, outlet holes1002, 1003, 1004 . . . pass over a limited region 1106 of the wafer1105. The wafer 1105 is inevitably developed at high rate at thislimited region as shown in FIG. 15. Therefore, the improvement of theuniformity in film thickness cannot be attained.

[0125] On the other hand, the outlet holes of the disk nozzle 1200according to the present invention are arranged as shown in FIG. 16. InFIG. 16, the outlet holes 1202, 1203, and 1204 are arranged such thatthey do not pass in a limited region while the wafer is being rotated(during the stirring process). When the disk nozzle 1200 is used, aregion through which the outlet hole 1202 passes shifts from thoseregions through which the outlet holes 1203 and 1204 passes as shown inFIG. 17.

[0126] In addition, the outlet holes pass through the region 1202 to1204 far less frequently than the holes of the conventional disk nozzle1000 (FIG. 14). Hence, the disk nozzle 1200 serves to improvedrastically the pattern dimension uniformity over the wafer. When thedeveloper is applied from the outlet holes, the wafer receives pressureat the portions located immediately below the outlet holes, which impairthe pattern dimension uniformity. To prevent this, the pressure belowthe outlet holes should be as small as possible. The total amount of thedeveloper supplied onto the wafer is predetermined. So it is desirablethat the amount of supplied developer per hole is less and the number ofthe holes is more when the developer is supplied in the predeterminedtime.

[0127] In Embodiment 4, the disk nozzle 1200 serves also as a developerholding member. Nonetheless, a developer holding member may be provided,besides the disk nozzle 1200. If so, the pH value the developer has at aposition right below an outlet hole differs from the pH value thedeveloper has at any position far from the outlet hole. To improve thedimension uniformity of the pattern formed on the wafer, the outputholes should be arranged as shown in FIG. 16, more preferably as shownin FIGS. 18 and 19. Furthermore, it is desirable that the outlet holesis distributed uniformly over the entire disk nozzle 1200.

[0128] In Embodiment 4, a developer film is formed by applying thedeveloper from the entire lower surface of the disk nozzle 1200, whilethe wafer is rotated at low speed. However, the method of forming a filmis not limited to this. A mechanism for suppressing foams (cause ofdefects) which are generated in the developer after the developer isapplied to the wafer, and a mechanism for supplying a developer to theentire wafer at the almost same time may be used as in Embodiments 5, 6and 7, which will be described below.

Embodiment 5

[0129] Embodiment 5 will be explained with reference to FIGS. 20 and 21.

[0130]FIG. 20 is a sectional view of a disk nozzle, explaining that adeveloping process is initiated by bringing a developer film (formed byvirtue of the assistance of surface tension) into contact with a wafer.To develop a resist film provided on the surface of a substrate such asa wafer, the developer film is formed on the surface of the disk nozzleby virtue of the surface tension. Then, the developer film is made incontact with the wafer, thereby initiating the development. Thedeveloper is applied to the entire surface of the wafer at a time. Airmay remain in a space between the surface of the developer liquid filmand the surface of the resist, but no fine foams are generated on thewafer surface. The foams generated at this time are large enough to riseto the upper surface of the developer liquid film. The developer liquidfilm, therefore, has no defects.

[0131] In the development unit, the developer may be slightly forcedfrom the nozzle holes 1601 by the pressure applied before the start ofthe development process. If so, adjacent developer droplets fromadjacent nozzle holes 1601 combine together due to the surface tension,forming a developer film 1602 on the nozzle surface (FIG. 20).

[0132] Subsequently, the wafer having a latent image formed on itssurface is lifted, together with a wafer holder (not shown), until itcontacts the developer liquid film 1602. The development is therebyinitiated. In this process, the developer is applied to the entireregion of the wafer, which is to be processed in a moment. Then thedeveloper is supplied through the nozzle holes as the distance betweenthe wafer and the nozzle is widened with the contact between thedeveloper and the nozzle. At last, the desired amount of the developeris discharged on the wafer and the distance is set at the predetermineddistance.

[0133] After the developer has been applied to it, the wafer is movedrelative to the disk nozzle holding the developer, as in Embodiments 1to 4. Upon lapse of 60 seconds from the start of the development, thedisk nozzle is moved up, and rinse solution is applied to the wafer,terminating the development. After rinsed thoroughly, the wafer isrotated at high speed, whereby the rinse solution is removed from thewafer. Post-baking is performed on the wafer at 130° C. for 90 seconds.The wafer is taken from the developing unit.

[0134] In the above explanation, the wafer is moved up to contact thedeveloper film. Nevertheless, the development may be initiated bydropping the developer liquid film onto the wafer, as shown in FIG. 21,by supplying air through the holes of the disk nozzle connected to anair supply system, after the developer liquid film has been formed.

[0135] In the above development process, the nozzle is moved to apredetermined distance, while the disk nozzle remains in contact withthe developer and while the developer is applied to the wafer from thedeveloper supply system through the nozzle holes, after the wafer hascome in contact with the developer film. Instead, after the wafer hascome in contact with the developer film, the distance between the waferand the nozzle may be set at the predetermined distance and then thespace may be filled with the developer.

Embodiment 6

[0136] Embodiment 6 will be explained with reference to FIGS. 22A to22C.

[0137]FIGS. 22A to 22C are sectional views of a disk nozzle having acenter portion slightly protruding. A method of developing wafer byusing this disk nozzle will be explained.

[0138] To prevent generation of foams during the process of forming adeveloper film, it is effective to employ a disk nozzle having a centerportion that protrudes slightly. Air is forced out from the developer,thereby preventing foams from being made when the developer is mountedon the wafer.

[0139] The wafer having a latent image formed on it is transported intothe development unit. A disk nozzle 1801 is used, which is circular asviewed from the bottom. The center part of the disk nozzle 1801 slightlyprotrudes, as shown in FIG. 22A.

[0140] The disk nozzle 1801 is spaced from the wafer by a distance of 2mm. Developer 1800 is applied onto the wafer as shown in FIG. 22B. Atthe same time, the wafer is rotated at 60 rpm, whereby the developerspreads itself over the entire surface of the wafer. The developer 1802is applied until it contacts the disk nozzle 1801, forming a film 1802as is illustrated in FIG. 22C.

[0141] During the development step, the wafer of the present inventionis moved relatively to the disk nozzle holding the developer in the samemanner as explained in Embodiments 1 to 4. Upon lapse of 60 seconds fromthe start of the development, the disk nozzle 1801 is moved up, andrinse solution is applied to the wafer, thereby terminating thedevelopment process. After thoroughly rinsed, the wafer is rotated athigh speed, whereby the rinse solution is removed from the wafer. Thepost-baking is performed on the wafer at 130° C. for 90 seconds. Thewafer is taken from the development unit.

[0142] Since the surface of the disk nozzle is curved, a space isprovided in the wafer peripheral region between the nozzle surface andthe wafer surface. Air is forced out through this space. No foams aregenerated. Therefore, the number of defects is reduced after completionof the development.

[0143] As described above, the developer is supplied from the nozzleholes, directly to the wafer. Instead, the developer liquid film formedon the surface of the nozzle may be set into contact with the wafer toinitiate the development, as in Embodiment 5. Alternatively, thedeveloper liquid film may be dropped onto the wafer to start thedevelopment, by supplying air from an air supply system.

[0144] Moreover, the same effect may be expected as the aboveembodiment, if the substrate surface facing the nozzle is in a convexform during the developer supply.

Embodiment 7

[0145] Embodiment 7 will be described with reference to FIG. 23.

[0146]FIG. 23 is a sectional view of a disk nozzle, explaining a methodof applying developer to the wafer by creating a low vacuum between thedisk nozzle and the wafer by use of a liquid/gas evacuating pump.

[0147] As the way to prevent generation of foams when the developer isapplied, the apparatus provides a cover (wall) between the wafer and theperiphery of the disk nozzle, thereby providing a space and to connectthis space to the liquid/gas evacuating pump. When the space isevacuated by a liquid/gas pump, generating a vacuum, the developer ispushed out of the nozzle holes and the developer is applied from thedisk nozzle onto the wafer. The developer is thereby applied to theentire surface of the wafer almost at a time. Since air is removed asmentioned above, virtually no foams are generated in the developer filmformed on the wafer.

[0148] A cover 1901 having a height of 2 mm is provided under the disknozzle 1903 and on the wafer. The cover 1901 and the disk nozzletherefore shields, like a cap, the main surface of the wafer. A part ofthe cover 1901 is connected with the liquid/gas pump. Air is drawn fromthe space provided between the disk nozzle 1903 and the cover 1901 bythe evacuation of the space with the liquid/gas pump. At the same time,the developer 1900 is forced out from the disk nozzle 1903 through thenozzle holes 1902. The developer 1900 is thereby applied to the wafer.When the developer 1900 is supplied to a desired amount into the spacebetween the wafer and the disk nozzle 1903, the liquid/gas pump isstopped. Then, in order to move the wafer relatively to the cover andthe disk nozzle, the liquid/gas pump is run reversely.

[0149] The wafer W of the present invention is moved relative to thedisk nozzle holding the developer, as in Embodiments 1 to 4. Upon lapseof 60 seconds from the start of the application of developer, the disknozzle 1903 is moved up. A rinse solution is then applied to the wafer,thereby terminating the development. After thoroughly rinsed, the waferW is dried while spinning. Post-baking is performed on the wafer W at130° C. for 90 seconds. Then, the wafer W is taken from the developmentunit.

[0150] To lift the cover and the disk nozzle, the liquid/gas pump isoperated reversely in the aforementioned example. Alternatively, theliquid/gas pump may be stopped after the developer has been applied in adesired amount, and additional developer or air is applied through thenozzle holes, thereby to lift the cover and the disk nozzle.

[0151] In the embodiments described above, the developer liquid film isformed directly on the wafer. A liquid film such as a water film, whichcannot develop the film, may be formed before the formation of thedeveloper liquid film. The developer liquid film may then be formed,while the liquid film (water film) is being removed from the wafer.Thus, the dimension uniformity of the formed pattern can be wellimproved, and defects can be reduced.

[0152] As described above, the substrate processed in the aforementionedembodiments is a semiconductor wafer. Nonetheless, the method andapparatus of the present invention can be applied to other substrates,such as a liquid crystal display substrate and an exposure masksubstrate.

[0153] The development process carried out in the embodiments describedabove is designed to form a photosensitive resin pattern. However, themain feature of the invention resides in bringing the liquid agentholding member into contact with part of the liquid agent and by movingthe holding member or the substrate during the wet process. The startingreaction materials and the reaction products in the liquid agenttherefore have uniform concentrations in the region where they contactthe substrate surface. So the dimension uniformity of the pattern formedon the wafer is improved. Accordingly, the present invention can beapplied to a wet etching process and an apparatus for manufacturing achromium exposure mask.

[0154] The stirring method of the invention not only renders theconcentration of the liquid agent uniform all over the substratesurface, but also reduces the concentration of the reaction productsaccumulated on the substrate surface and increases the concentration ofthe starting materials of the liquid agent. Therefore, the processingrate can be also increased.

[0155] As has been described, the method of the present invention can beused to remove organic materials from a substrate, remove a photoresistpattern after etching, and remove a native oxide film from a siliconwafer. The present invention can be applied to Au plating of a substrateif an electrode is provided on the substrate and the liquid agentholding member and if a plating solution is used in place of the liquidagent.

[0156] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

1. A substrate processing method comprising: a first step of supplying aliquid agent onto a main surface of a substrate; a second step ofholding the liquid agent between the substrate and a liquid agentholding member by bringing an upper surface of a film of the liquidagent in contact with the liquid agent holding member which faces thesubstrate; and a third step of moving at least one element of thesubstrate and the liquid agent holding member in parallel to the mainsurface of the substrate, after the second step, in order to treatuniformly the main surface of the substrate with the liquid agent. 2.The substrate processing method according to claim 1 , wherein thesecond step includes a step of using a liquid agent supply nozzle as theliquid agent holding member.
 3. The substrate processing methodaccording to claim 1 , wherein the first step includes a step ofapplying the liquid agent, by use of a disc nozzle with plural liquidagent outlet holes or by use of a linear nozzle which has a lineardeveloper supply section whose length is almost the same as a diameterof the wafer, while rotating the substrate or moving the linear nozzlefrom one end of the substrate to the other in parallel to the mainsurface of the substrate which is at a sandstill.
 4. The substrateprocessing method according to claim 1 , wherein the second stepincludes a step of moving the liquid agent holding member so as to facethe substrate and bringing the liquid agent holding member in contactwith an upper surface of the film of the liquid agent.
 5. The substrateprocessing method according to claim 1 , wherein the third step includesa step of performing reciprocating movement or rotational movement. 6.The substrate processing method according to claim 5 , wherein therotational movement includes rotating the substrate while the liquidagent holding member is immobilized.
 7. The substrate processing methodaccording to claim 1 , wherein the velocity of the rotational movementis 10 to 50 rpm.
 8. The substrate processing method according to claim 1, wherein the first step includes a step of forming a singleliquid-agent film on a surface of the liquid agent supply nozzle facingthe substrate, supplying the liquid agent to the main surface of thesubstrate in the form of film, and using the liquid agent supply nozzleas the liquid agent holding member.
 9. The substrate processing methodaccording to claim 8 , wherein the first step includes a step ofsupplying the liquid agent to an entire surface of the substrate almostsimultaneously.
 10. The substrate processing method according to claim 8, wherein the first step includes a step of supplying the liquid agentonto the main surface of the substrate while a substrate surface facingthe liquid agent supply nozzle remains in a convex form.
 11. Thesubstrate processing method according to claim 3 , wherein the firststep includes a step of supplying the liquid agent by using the liquidagent supply nozzle having the surface made in a convex form.
 12. Thesubstrate processing method according to claim 1 , wherein the firststep includes a step of supplying the liquid agent while reducingpressure in a space provided between the substrate and the liquid agentsupply nozzle.
 13. The substrate processing method according to claim 1, wherein the liquid agent is one selected from the group consisting ofa developer, an etching solution, a washing solution, a remover agent, afilm formation solution and a plating liquid.
 14. The substrateprocessing method according to claim 1 , further comprising a step ofrinsing the liquid agent holding member simultaneously with the mainsurface of the substrate by replacing the liquid agent with a rinsesolution after the third step.
 15. A substrate processing apparatuscomprising: a table on which a substrate is to be mounted; a liquidagent supply nozzle for supplying a liquid agent onto a main surface ofthe substrate; a liquid agent holding member facing the substrate andmovable up and down in order to be in contact with an upper surface ofthe film-form liquid agent; and a mechanism for moving at least oneelement of the substrate and the liquid agent holding member in parallelto the main surface of the substrate while the liquid agent holdingmember is in contact with the upper surface of the film-form liquidagent.
 16. The substrate processing apparatus according to claim 15 ,wherein the liquid agent supply nozzle serves also as the liquid agentholding member.
 17. The substrate processing apparatus according toclaim 15 , wherein the mechanism includes a reciprocating drivemechanism or a rotational drive mechanism.
 18. The substrate processingapparatus according to claim 15 , wherein the liquid agent supply nozzlehas a plurality of liquid agent outlet holes in a surface facing thesubstrate, any two of the liquid agent outlet holes adjacent to eachother in a moving direction of the substrate passing through differentregions of the substrate when the nozzle moves relative to thesubstrate.
 19. The substrate processing apparatus according to claim 15, wherein the liquid agent supply nozzle has a plurality of liquid agentoutlet holes in a surface facing the substrate, the liquid agent outletholes being uniformly distributed in a plane facing the substrate.